The present invention relates to a method and apparatus for processing a substrate by spraying a processing solution onto the substrate.
The process of manufacturing a photo mask used in a liquid crystal display device, a semiconductor device or in the manufacture thereof includes a lithography step for forming a circuit pattern on a substrate such as a glass substrate, a semiconductor wafer or a quartz substrate by using the photo mask.
For forming a circuit pattern on the substrate in the lithography process, the steps of forming a resist pattern on the substrate, etching the substrate by using the resist pattern as a mask, removing the resist pattern after the etching step, and forming a film on the substrate having the resist pattern removed therefrom arc repeated a plurality of times.
Where the substrate is a photo mask used in the manufacture of a liquid crystal display device or a semiconductor device, an insoluble resist that is unlikely to be dissolved in a solvent is used for forming a pattern. If the pattern is formed by using the insoluble resist, it is difficult to peel off the pattern by the ordinary method. Thus, a plasma asking is employed for removing the resist pattern.
However, the plasma asking invites an increased manufacturing cost and a low through-put.
Under the circumstances, a new technique replacing the plasma asking is disclosed in, for example, Japanese Patent Disclosure (Kokai) No. 6-29270 and Japanese Patent Disclosure No. 6-291098. Specifically, it is disclosed that the resist pattern is peeled off by using a mixed solution consisting of sulfuric acid and hydrogen peroxide solution, followed by supplying a pure water onto the substrate for the rinsing treatment.
However, the prior art exemplified above is defective in that, in rinsing the substrate with a pure water after peeling of the resist pattern off the substrate with the mixed solution, the pure water tends to bring about a dissolving reaction with the sulfuric acid remaining on the substrate. What should be noted is that the dissolving reaction brings about the mist generation and scattering of the sulfuric acid.
An object of the present invention is to provide a method and apparatus for processing a substrate, which permits suppressing the dissolving reaction between sulfuric acid used as a first process solution and a rinsing solution used as a second process solution in the case where the substrate is processed with the second process solution after the processing with the first process solution.
According to a first aspect of the present invention, there is provided a method of processing a substrate, in which the substrate is processed successively with a plurality of different kinds of process solutions, comprising:
a first step of processing the substrate with a first process solution prepared by mixing sulfuric acid and hydrogen peroxide solution;
a second step of supplying a hydrogen peroxide solution alone to the substrate after completion of the processing with the first process solution; and
a third step of supplying a second process solution for rinsing the substrate to the substrate after supply of the hydrogen peroxide solution alone for a predetermined period of time.
According to another aspect of the present invention, there is provided an apparatus for processing a substrate, in which the substrate is successively processed with a plurality of different kinds of process solutions, comprising:
a spin chuck supporting the substrate;
a driving source for rotating the spin chuck;
a nozzle member for supplying a first process solution prepared by mixing sulfuric acid and a hydrogen peroxide solution at a predetermined mixing ratio to the substrate supported by the spin chuck and second process solution for rinsing the substrate to the substrate;
a switching mechanism for selecting sulfuric acid; the hydrogen peroxide solution and the second process solution supplied to the nozzle member;
a concentration adjusting mechanism for adjusting the mixing ratio of sulfuric acid to the hydrogen peroxide solution, which collectively form the first process solution, supplied to the nozzle member;
and a control device for controlling the supply of sulfuric acid, the hydrogen peroxide solution and the second process solution, which is switched by the switching mechanism, and the adjustment of the mixing ratio of sulfuric acid to the hydrogen peroxide solution, which is performed by the concentration adjusting mechanism.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.